1. Field of the Invention
This invention relates to a control system of electrically memorizing the distance between a first and a second member which are in a relative distance variable relation with each other on a straight line, reading the memorized distance between the two members, when necessary, and reproducing the distance between the two members at any time; and to a control device for memorizing and reading the reproducing the position of a stool or a chair such as used with dentists, physicians, barbers, beauty specialists and the like.
2. Prior Art
Heretofore, this kind of control system of or device for reading and reproducing the memory which has been used is of the system or device in which a position detection device including a potentiometer is brought into interlocking with a material to be controlled in response to the position of the material, the position of the material is read in terms of a resistance value of the potentiometer and thereafter the resistance value is memorized as a resistance value by another motor-interlocking potentiometer provided through a contact relay (for example, Japanese patent publication No. 151291/1977). But according to this system, it is not only inevitable to provide a mechanically interlocking mechanism between a position detection potentiometer and a material to be controlled and difficult to mount a position detection device but also the potentiometer is in an interlocking relation with the material to controlled, and accordingly, when the material is moved, the resistor and a slider cause wear by slide contact between them irrespective of manual or automatic operation, with the result that the resistance value detected is reduced in relability and in addition thereto, the mechanical error of the interlocking mechanism in combination with the reduced reliability further reduce reliability. To eradicate this vicious cycle, it is necessary to use the position detection potentiometer in a non-heating area and this in turn makes it necessary to use a highly reliable and expensive potentiometer. This interlocking mechanism must also be accurate, which in turn added to production cost. This is a disadvantage. Also, when the memorized position of the material is reproduced and controlled by comparing the resistance value of the motor interlocking potentiometer with that of the position detection potentiometer provided through the contact of a relay or the like. Accordingly, in the above-described control system of memorizing, reading and reproducing, a position of a material to be controlled, a control circuit for position detection and memory, position reading, etc. is of complicated structure including a relay and the like, and wear of the contact of the relay reduces the reliability of reproducibility in the system. This is another disadvantage. This invention has been accomplished to obviate the disadvantages of the conventional control system of memorizing, reading and producing a position of a material to be controlled and has a very wide range of application.